From: Muchun Song songmuchun@bytedance.com
[ Upstream commit e583b5c472bd23d450e06f148dc1f37be74f7666 ]
The flush_cache_page() only remove a PAGE_SIZE sized range from the cache. However, it does not cover the full pages in a THP except a head page. Replace it with flush_cache_range() to fix this issue. This is just a documentation issue with the respect to properly documenting the expected usage of cache flushing before modifying the pmd. However, in practice this is not a problem due to the fact that DAX is not available on architectures with virtually indexed caches per:
commit d92576f1167c ("dax: does not work correctly with virtual aliasing caches")
Link: https://lkml.kernel.org/r/20220403053957.10770-3-songmuchun@bytedance.com Fixes: f729c8c9b24f ("dax: wrprotect pmd_t in dax_mapping_entry_mkclean") Signed-off-by: Muchun Song songmuchun@bytedance.com Reviewed-by: Dan Williams dan.j.williams@intel.com Reviewed-by: Christoph Hellwig hch@lst.de Cc: Alistair Popple apopple@nvidia.com Cc: Al Viro viro@zeniv.linux.org.uk Cc: Hugh Dickins hughd@google.com Cc: Jan Kara jack@suse.cz Cc: "Kirill A. Shutemov" kirill.shutemov@linux.intel.com Cc: Matthew Wilcox willy@infradead.org Cc: Ralph Campbell rcampbell@nvidia.com Cc: Ross Zwisler zwisler@kernel.org Cc: Xiongchun Duan duanxiongchun@bytedance.com Cc: Xiyu Yang xiyuyang19@fudan.edu.cn Cc: Yang Shi shy828301@gmail.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- fs/dax.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/dax.c b/fs/dax.c index cd03485867a7..411ea6a0fe57 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -846,7 +846,8 @@ static void dax_entry_mkclean(struct address_space *mapping, pgoff_t index, if (!pmd_dirty(*pmdp) && !pmd_write(*pmdp)) goto unlock_pmd;
- flush_cache_page(vma, address, pfn); + flush_cache_range(vma, address, + address + HPAGE_PMD_SIZE); pmd = pmdp_invalidate(vma, address, pmdp); pmd = pmd_wrprotect(pmd); pmd = pmd_mkclean(pmd);